Organic Electronic Component Comprising A Patterned, Semi-Conducting Functional Layer And A Method For Producing Said Component

ABSTRACT

The invention relates to an organic electronic component such as an organic field effect transistor and a method for producing said component, the semiconducting layer of the component being patterned, although the component can be produced by an inexpensive printing method. In order to achieve this, the lower functional layer is prepared by a treatment such that it has partial regions on which wetting takes place in the subsequent process step, and partial regions on which wetting is hot effected.

The invention relates to an organic electronic component such as anorganic field effect transistor and a method for producing saidcomponent, the semiconducting layer of the component being patterned.

In the case of organic electronic components, the organic semiconductingfunctional layers are usually applied in large-area fashion byspin-coating, spraying on, squeegeeing or the like as homogeneouslarge-area but very thin functional layers.

In an integrated circuit, that may lead to problems since leakagecurrents arise from one component or from one electrode to the next ifthe semiconducting functional layers of the components adjoin oneanother. Said leakage currents disrupt the performance of the circuit insome instances, considerably. Therefore, attempts are made to patternthe semiconducting functional layers and/or to reduce them to the activeareas, that is to say the regions where current channels form. Thispatterning can be achieved by means of corresponding exposure masks inthe case of components produced photolithographically. Componentsproduced photolithographically become too expensive, however, for broadapplication. Therefore, the focus is on inexpensive printing productionmethods for the development of the elements.

However, the semiconducting functional layer cannot be applied inpatterned fashion by conventional printing method because this layermust be very thin (typically less than 100 nm) in order for it tofunction. The layer thicknesses required for the semiconductingfunctional layer, for example, can conventionally be achieved only bymeans of a coating process such as coating, spraying on, etc.

It is an object of the present invention to make it possible, in thecase of organic electronic components produced in printed fashion, topattern a thin, in particular the semiconducting functional layerwithout in this case increasing the layer thickness of the affectedfunctional layer in comparison with a, e.g. semiconducting, functionallayer normally produced by a coating process (coating, spraying on,squeegeeing).

The, invention relates to an organic electronic component comprising apatterned semiconducting functional layer having a thickness of lessthan 100 nm, the patterning arising by virtue of a lower functionallayer being only partially wetted with the organic functional materialof the next functional layer. The invention additionally relates to amethod for producing an organic electronic component, in which, throughtargeted treatment of a lower functional layer, an upper functionallayer is produced in patterned fashion despite large-area application.

According to one embodiment of the method, a semiconducting layer isproduced in patterned fashion.

According to one exemplary embodiment, the lower functional layer ispartially covered by a resist that can be applied with a very smalllayer thickness by printing.

Semiconducting, insulating, and/or conductive organic functional layers,but of course also inorganic functional layers, such as e.g. thin metallayers, can be produced in patterned fashion by the method as upper,patterned functional layers.

Depending on the construction of the organic electronic component andthe upper layer, the lower functional layer is the substrate, aconductive functional layer, etc.

The term “targeted treatment” denotes the partial coverage and/or thelocal alteration of the lower functional layer, which has the effectthat, in selected regions of the lower functional layer, in the course,of coating with the material, wetting takes place or is avoided (that isto say “partial wetting” takes place), and can be effected by means of aprinting method, by laser treatment, thermal treatment, other physical,electrical or chemical treatment, but always partially and with aresolution in the μm range. By way of example, mention shall be made ofpartial contact-making with acid/base or ocher reactive chemicalsubstances, physical effects such as light, heat, cold, and finallymechanical treatment such as rubbing. The treatment has the consequencein any event that tie next functional layer does not undergo wetting onthe treated locations or undergoes wetting only there.

The term “organic material” and/or “functional polymer” here encompassesall types of organic, organometallic and/o inorganic plastics. Itconcerns all types of substances with the exception of thesemiconductors that form the traditional diodes (germanium, silicon) andthe typical metallic conductors. Accordingly, a restriction in thedogmatic sense to organic material as material containing carbon is notenvisaged, rather the broad use of e.g. silicones is also conceived of.Furthermore, the term is not intended to be subject to any restrictionwith regard to the molecular size, in particular to polymeric and/oroligomeric materials, rather the use of “small molecules” is alsoentirely possible.

The invention will be explained below with reference to two figuresshowing a plan view and a cross section through an exemplary embodimentof an organic electronic component according to the invention:

FIG. 1 shows a plan view of a circuit having a patterned semiconductingfunctional layer. An organic circuit constructed on a substrate(concealed) can be seen. A plurality of active elements such as organicfield effect transistors are arranged one beside the other; thesource/drain electrodes 2 can be discerned in each case. The hatchedregion shows the organic semiconductor layer 1, which is patterned andhas partial regions 3 which are free of semiconducting functionalmaterial. The free region 3 (“free” in this case means covered neitherwith conductive nor with semiconducting material) suppresses a leakagecurrent from the left-hand region into the right-hand region of thecircuit.

FIG. 2 shows an OFET having the substrate 4 and the source/drainelectrodes 2. Situated on the conductive functional layer, thesource/drain electrodes 2, is the patterned semiconducting functionallayer 1, which does not extend over the conductive functional layer 2 inwhole-area fashion, but rather is interrupted by the resist 6, whichpartially covers the substrate 4 against wetting with semiconductingfunctional layer 1, in other words said semiconducting functional layercovers in patterned fashion only the active areas, that is to say theareas above the source/drain electrodes. The semiconducting functionallayer for its part is covered by the insulating functional layer 5, onwhich the gate electrodes 7 are situated.

The invention relates to an organic electronic component such as anorganic field effect transistor and a method for producing saidcomponent, a thin layer, such as the semiconducting layer of thecomponent being patterned, although the component can be produced-by aninexpensive printing method. In order to achieve this, the lowerfunctional layer is prepared by a treatment such that it has partialregions on which betting takes place in the subsequent process step, andpartial regions on which wetting is not effected.

1. An organic electronic component comprising a patterned functionallayer having a thickness of less than 100 nm, the patterning arising byvirtue of a lower functional layer being only partially wetted with theorganic functional material of the next functional layer.
 2. The organicelectronic component as claimed in claim 1, in which the patternedfunctional layer is a semiconducting functional layer.
 3. A method forproducing an organic electronic component, in which, through targetedtreatment of a lower functional layer, an upper functional layer isproduced in patterned fashion despite large-area application.
 4. Themethod as claimed in claim 3, in which a semiconducting functional layeris produced in patterned fashion.
 5. Tile method as claimed in claim 4,in which the lower functional layer is partially covered by a resistthat can be applied with a very small layer thickness by printing.